Public health officials in the Oregon Department of Human Services were notifying physicians today that mumps cannot be confirmed in most of the patients thought to have had the illness.

Since April, 58 cases of mumps have been reported to health officials, and 53 had tested positive by lab culture. However, Oregon public health laboratory staff became concerned when they detected inconsistencies in the tests, said Paul Cieslak, M.D., DHS communicable disease manager.

"Because of these irregularities, we can no longer definitively say that these people had mumps," said Cieslak. "We know that many were ill with parotid gland swelling, which makes us think of mumps; but until we have more clarity about the testing, we are calling these suspect cases."

Local health department staff are notifying physicians of the new laboratory findings.

Cieslak said that one case still meets the confirmed definition.

"We regret the confusion this has caused," Cieslak said. “The epidemiology of communicable diseases is always changing, and we’ll have to deal with this new information. The good news is that if the illness we’ve been seeing isn’t mumps, it’s much less likely to spread rapidly to others."

Patients who have questions or are concerned about their case status should call their health care provider, Cieslak said.

Oregon public health laboratory and epidemiology staff are working closely with the federal Centers of Disease Control and Prevention to resolve the issue, which is specific to mumps testing, and unrelated to other lab testing processes, Cieslak said.